Particulate matter (PM), also known as particle pollution, includes the tiny particles of fly ash and dust that are expelled from coal-burning power plants. Particulate pollution is a mixture of soot, smoke, and tiny particles formed in the atmosphere from sulfur dioxide (SO2), nitrogen oxides (NOx) and ammonia (NH3). Fine particles are a mixture of a variety of different compounds and pollutants that originate primarily from combustion sources such as power plants, but also diesel trucks and buses, cars, etc. They are sometimes referred to as PM2.5 (particulate matter smaller than 2.5 microns in diameter - less than one-hundredth of the width of a human hair). Fine particles are either emitted directly from these combustion sources or are formed in the atmosphere through complex oxidation reactions involving gases, such as sulfur dioxide (SO2) or nitrogen oxides (NOX). Among particles, fine particles are of gravest concern because they are so tiny that they can be inhaled deeply, thus evading the human lungs' natural defenses.[1]

U.S. Regulations

In 1923, the first electrostatic precipitator was employed in a coal plant, which used electrical fields to remove particulate matter from a boiler's flue gas, like static electricity causing dust to cling to certain types of materials. Electrostatic precipitators, along with baghouses (which work like large industrial-scale vacuum cleaners to capture ash and dust particles in felt or woven fabric bags), have been used to reduce the release of soot-forming particulate matter, but some still escapes, leading to negative health effects.[2]

Since 1997 coarse (diameter greater than 2.5 μm) and fine (diameter between 0.1 μm and 2.5 μm) particles have been regulated by the EPA, but ultrafine particles (diameter less than 0.1 μm) remain unregulated.[4] Roughly 80% of the ash falls into an ash hopper, but the rest of the ash then gets carried into the atmosphere to become fly ash.[5]

A 2009 court ruling concluded that the EPA standards for the amount of soot permissible in the air on an annual average ignored the advice of scientific advisers by maintaining the standard established in 1997 and must be rewritten. That limit was 15 micrograms per cubic meter of air.[6]

In a motion filed on December 7, 2010, the EPA asked for an extension in the current court-ordered schedule for issuing the new rules, which would cut emissions of pollutants including mercury and soot. EPA is under court order to issue final rules on January 16, 2011, but is seeking to extend the schedule to finalize the rules by April 2012.[7]

On June 15, 2012, EPA proposed to lower standards for particulate matter to between 12 and 13 micrograms per cubic meter (μg/m3). The agency is also taking “public comment on alternative annual standard levels down to 11 μg/m3.”

In December 2012 the EPA issued its final soot rules, tightening the federal soot standards by 20 percent - the most protective measure laid out in its June 2012 draft rule (12 micrograms per cubic meter of air). The agency will determine which areas are out of attainment in 2014, and the communities will then have six years to comply. The EPA estimates that 66 of the nation’s 3,033 counties will be found in violation of the new standard. It projects seven — all in California — will still be out of compliance by 2020.[8]

Health effects

Carcinogen

In October 2013 the World Health Organization's International Agency for Research on Cancer said both air pollution and "particulate matter" would now be classified among its Group 1 human carcinogens. They cited data indicating that in 2010, over 220,000 deaths from lung cancer worldwide resulted from air pollution, and said there was also convincing evidence it increases the risk of bladder cancer. Depending on the level of exposure in different parts of the world, the risk was found to be similar to that of breathing in second-hand tobacco smoke.[9]

Other effects

Studies have shown that exposure to particulate matter is also related to an increase of respiratory and cardiac mortality. Particulate matter can irritate small airways in the lungs, which can lead to increased problems with asthma, chronic bronchitis, airway obstruction, and gas exchange. Several studies have also shown a correlation between coal-related air pollutants and stroke. In Medicare patients, ambient levels of PM2.5 have been correlated with cerebrovascular disease, and PM10 with hospital admission for ischemic stroke, which accounts for eighty-seven percent of all strokes. The size and chemical composition of these particles affects the impacts on human health. [10][11]

According to a report by the Clean Air Task Force, the health effects from fine particle air pollution include death, hospitalizations, emergency room visits, asthma attacks, and a variety of lesser respiratory symptoms. Key findings include:[12][1]

Fine particle pollution from U.S. power plants cuts short the lives of over 30,000 people each year.

In more polluted areas, fine particle pollution can shave several years off its victims' lives.

Hundreds of thousands of Americans suffer from asthma attacks, cardiac problems and upper and lower respiratory problems associated with fine particles from power plants.

The elderly, children, and those with respiratory disease are most severely impacted by fine particle pollution from power plants.

According to the American Lung Association, particle pollution can damage the body in ways similar to cigarette smoking, helping explain why particle pollution can cause heart attacks and strokes. However, even short-term exposure to particle pollution can kill: peaks or spikes in particle pollution can last for hours to days. Deaths can occur on the very day that particle levels are high, or within one to two months afterward.[13]

A 2010 yearlong Pittsburgh Post-Gazette investigation found that Allegheny and Westmoreland counties and the rest of southwestern Pennsylvania - which are near multiple coal plants - show higher mortality rates for multiple sclerosis. The newspaper notes that studies suggest particulate matter pollution can trigger, aggravate or cause relapses of the autoimmune disease.[14]

CO2 and particulate matter

A 2009 study, “Enhancement of Local Air Pollution by Urban CO2 Domes,” published in Environmental Science & Technology by Mark Z. Jacobson, found that domes of increased carbon dioxide concentrations – discovered to form above cities more than a decade ago – cause local temperature increases that in turn increase the amounts of local air pollutants, raising concentrations of health-damaging ground-level ozone as well as particulate matter in urban air.

According to Jacobson: "Warming increases water vapor, and both water vapor and higher temperatures increase ozone where the ozone is already high but have less effect where the ozone is low. Carbon dioxide domes over cities increase temperatures over the cities above and beyond the heat island effect, and these higher temperatures increase water vapor, and both higher water vapor and higher temperatures increase the rates of chemical air pollution production over cities relative to rural areas. The results suggest a causal nature of increased air pollution mortality due to increased carbon dioxide where the air pollution is already high. Thus, controlling CO2 emissions at the local level will reduce air pollution and the resulting air pollution mortality."

Jacobson’s estimates that “reducing local CO2 may reduce 300-1000 premature air pollution mortalities/yr in the U.S. and 50-100/yr in California, even if CO2 in adjacent regions is not controlled.”

Health costs

In 2010, Abt Associates issued a study commissioned by the Clean Air Task Force, a nonprofit research and advocacy organization, quantifying the deaths and other health effects attributable to fine particle pollution from coal-fired power plants.[15] The study found that over 13,000 deaths and tens of thousands of cases of chronic bronchitis, acute bronchitis, asthma-related episodes and asthma-related emergency room visits, congestive heart failure, acute myocardial infarction, dysrhythmia, ischemic heart disease, chronic lung disease, peneumonia each year are attributable to fine particle pollution from U.S. coal-fired power plants. Abt assigned a value of $7,300,000 to each 2010 mortality, based on a range of government and private studies. Valuations of illnesses ranged from $52 for an asthma episode to $440,000 for a case of chronic bronchitis.[16]

Click here to see the total estimated heath effects and costs for each U.S. coal power plant.

EPA finds Clean Air Act benefits will add up to $2 trillion by 2020, mainly from PM regulations

Avoided Health Impacts: 2010 and 2020 (projected)

According to an EPA report released in March 2011, "The Benefits and Costs of the Clean Air Act from 1990 to 2020", the annual dollar value of benefits of air quality improvements from 1990 to 2020 will reach a level of approximately $2.0 trillion in 2020. The benefits would be achieved as a result of Clean Air Act Amendment-related programs and regulatory compliance actions, estimated to cost approximately $65 billion by 2020.

Most of the benefits (about 85 percent) are attributable to reductions in premature mortality associated with reductions in ambient particulate matter: "as a result, we estimate that cleaner air will, by 2020, prevent 230,000 cases of premature mortality in that year" (Introduction). The remaining benefits are roughly equally divided among three categories of human health and environmental improvement: preventing premature mortality associated with ozone exposure; preventing morbidity, including acute myocardial infarctions and chronic bronchitis; and improving the quality of ecological resources and other aspects of the environment.

According to the report: "The very wide margin between estimated benefits and costs, and the results of our uncertainty analysis, suggest that it is extremely unlikely that the monetized benefits of the CAAA over the 1990 to 2020 period reasonably could be less than its costs, under any alternative set of assumptions we can conceive. Our central benefits estimate exceeds costs by a factor of more than 30 to one, and the high benefits estimate exceeds costs by 90 times. Even the low benefits estimate exceeds costs by about three to one."

Coal-fired power plants produce more hazardous air pollution in the United States than any other industrial pollution sources;

More than 400 coal-fired power plants located in 46 states across the country release in excess of 386,000 tons of hazardous air pollutants into the atmosphere each year;

Particulate matter pollution from power plants is estimated to kill approximately 13,000 people a year. Most coal-fired plants are concentrated in the Midwest and Southeast.

Soot and global warming

Particulate pollution is a mixture of soot, smoke, and tiny particles formed in the atmosphere from sulfur dioxide (SO2), nitrogen oxides (NOx) and ammonia (NH3). Soot, or black carbon, is made up of tiny carbon particulate matter that contributes to global warming by absorbing heat in the atmosphere and reducing albedo, the reflection of sunlight, when deposited on snow and ice. In a paper published in May 2008 in Nature Geoscience, researchers found that black carbon soot may play a larger role than previously thought in global warming.[17] A 2010 USAID study identified black carbon as the second or third largest contributor to the current anthropogenic global warming, surpassed only by carbon dioxide and methane.[18]